You have no concerns about a dominatrix in a dungeon wielding a razor, but you're freaking out over the mere thought of contracting HIV via micro-abrasions from razor cuts you could not even notice????? Hmmm . . . dude, it's time you considered reprioritizing your health risks!

Your HIV fears are unfounded. HIV does not survive very long outside the body, for one thing. And you mention the disposable razor looked new and you did not get cut. Although I do not feel it is at all necessary, if you remain worried about HIV, get a single HIV-antibody test at the three-month mark to put your unwarranted fears permanently to rest. And if you still can't stop worrying, I'll have to come over there and give you a spanking, you naughty boy you.

I guess these days you can buy Anusol via the automatic tills in supermarkets so it's a bit less embarrassing than it would have been in days or yore.

Piles anecdote (which is appropriately enough, pretty shitty): when my mate at primary school told me her older brother had piles I wondered why this was a bad thing, since surely everyone would want piles of money.

In some cases Thrombocid (cream ointment, I do not know if this is sold in UK or what is its equivalent) solves the problem quickly.
If that is related to internal hemorrhoids I would recommend that you go to a proctologist.